Hi oldmegan,
I can empathise with what your going through, not the personal, but the depression, maybe the first thing would be to get it diagnosed, so possibly a visit to the docs might be in order.
I went through a really bad patch not so long ago, highs and lows, the whole ish, so I had a look on the web, and came up with this site, haven't used it yet, but I just may.
But whatever, I wish you well, and sincerely hope things get better for you.
http://www.mind1st.co.uk/fish-oil-depression.a sp